TraceId

Go pkg to propagate TraceId header across multiple services.

Enables simple tracing capabilities and log grouping.
The value can be exposed to end-users in case of an error.
The value is UUIDv7, which lets you infer the timestamp.
Unlike OTEL, this package doesn't trace spans or metrics, doesn't require any backend and doesn't have large dependencies (GRPC).

Example - HTTP middleware

package main

import (
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/go-chi/httplog/v2"
	"github.com/go-chi/traceid"
)

func main() {
	r := chi.NewRouter()

	r.Use(traceid.Middleware)
	r.Use(httplog.RequestLogger(logger()))
	r.Use(middleware.Recoverer)

	r.Use(func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

			// Log traceId to request logger.
			traceID := traceid.FromContext(r.Context())
			httplog.LogEntrySetField(ctx, "traceId", slog.StringValue(traceID))

			next.ServeHTTP(w, r.WithContext(ctx))
		})
	})

See example/main.go

Example: Send HTTP request with TraceId header

import (
	"github.com/go-chi/traceid"
)

func main() {
	// Set TraceId in context, if not set from parent ctx yet.
	ctx := traceid.NewContext(context.Background())

	// Make a request with TraceId header.
	req, _ := http.NewRequestWithContext(ctx, "GET", "http://localhost:3333/proxy", nil)
	traceid.SetHeader(ctx, req)

	resp, err := http.DefaultClient.Do(req)
	//...
}

Example: Set TraceId header in all outgoing HTTP requests globally

import (
	"github.com/go-chi/traceid"
	"github.com/go-chi/transport"
)

func main() {
	// Send TraceId in all outgoing HTTP requests.
	http.DefaultTransport = transport.Chain(
		http.DefaultTransport,
		transport.SetHeader("User-Agent", "my-app/v1.0.0"),
		traceid.Transport,
	)
	
	// This will automatically send TraceId header.
	req, _ := http.NewRequest("GET", "http://localhost:3333/proxy", nil)
	_, _ = http.DefaultClient.Do(req)
}

Get time from UUIDv7 value

$ go run github.com/go-chi/traceid/cmd/traceid 018e0ee7-3605-7d75-b344-01062c6fd8bc
2024-03-05 14:56:57.477 +0100 CET

You can also create a new UUIDv7:

$ go run github.com/go-chi/traceid/cmd/traceid
018e0ee7-3605-7d75-b344-01062c6fd8bc

License

MIT